Within the next couple of weeks, a remote part of north-western Tasmania is likely to grab headlines around the world as a major climate change marker is passed.
The aptly named Cape Grim monitoring site jointly run by CSIRO and the Bureau of Meteorology will witness the first baseline reading of 400 parts per million (ppm) of carbon dioxide in the atmosphere, researchers predict.
“Once it’s over [400 ppm], it won’t go back,” said Paul Fraser, dubbed by CSIRO as the Air Man of Cape Grim, and now a retired CSIRO fellow. “It could be within 10 days.”
The most recent reading on May 6 was 399.9 ppm, according to readings compiled by the CSIRO team led by Paul Krummel that strip out influences from land, including cities such as Melbourne to the north. (See chart below, with the red line showing the baseline CO2.)
The approaching global CO2 threshold comes as climate change looks like becoming one of the key issues in Australia’s election campaign.
The Turnbull government has made clear it will oppose Labor’s proposals for an emissions trading scheme that will again put a price on carbon pollution.